Stabilized liquid detergent composition

ABSTRACT

STABLE CONTROLLED SUDSING HEAVY-DUTY LIQUID DETERGENT COMPOSITIONS CONTAINING ANIONIC DETERGENTS SUCH AS BIODEGRADABLE ALKYL OR ALKARYL SULFONATES AND SULFATES OR ALKYLPOLYETHOXY SULFONATES ARE PROVIDED BY THE INCLUSION OF SMALL AMOUNTS OF AN ALKALI METAL SALT OF A FATTY ACID SUCH AS MYRISTIC OR COCO FATTY ACIDS OR MIXTURES THEREOF, IN COMBINATION WITH AN ALKANOLAMIDE SUCH AS ALURIC DIETHANOLAMIDE. THE WEIGHT RATIO OF FATTY ACID TO ALKANOLAMIDE IS ABOUT 1:2 OR 1:11.

United States Patent 3,707,503 STABILIZED LIQUID DETERGENT COMPOSITION Terrence G. Kenny, Park Ridge, NJ assignor to Lever Brothers Company, New York, N .Y. No Drawing. Filed Nov. 25, 1970, Ser. No. 92,855 Int. Cl. C11d 9/30 US. Cl. 252-417 4 Claims ABSTRACT OF THE DISCLOSURE Stable controlled sudsing heavy-duty liquid detergent compositions containing anionic detergents such as biodegradable alkyl or alkaryl sulfonates and sulfates or alkylpolyethoxy sulfonates are provided by the inclusion of small amounts of an alkali metal salt of a fatty acid such as myristic or coco fatty acids or mixtures thereof, in combination with an alkanolamide such as lauric diethanolamide. The Weight ratio of fatty acid to alkanolamide is about 1:2 or 1:11.

BACKGROUND OF THE INVENTION Field of the invention Detergent compositions.

DESCRIPTION OF THE PRIOR ART Heavy-duty liquid detergent compositions, and especially those relying on non-soap synthetic anionic systems for detergency or cleaning action, have been used successfully in cleaning a variety of surfaces and materials and particularly afford excellent soil removal characteristics for washing heavily soiled fabrics and the like.

Such detergent compositions, particularly those which contain linear alkyl or alkaryl sulfonates or sulfates in combination with nonionic amide-type active systems do not always give their best cleansing performance when employed in certain conditions, such as in washing clothes, because the suds formed at concentrations required for good cleaning tend to cushion the movement of the clothes being washed, and diminish agitation to the point Where inefficient cleansing results. In addition, this tendency to produce extremely high levels of stable suds during the wash cycle further manifests itself in the rinse cycle, in that oftentimes the suds cannot be completely dissipated in the rinsing process.

Accordingly, there has arisen a demand for detergent compositions which possess superior heavy-duty cleansing power with depressed suds producing capabilities.

Efforts to solve this problem thus recognized has taken many paths. For example, the oversudsing in active systems which contain anionic detergents in combination with nonionic amide-type detergents can be solved by simply reducing or eliminating the amide, since it is known that the amide contributes greatly to suds boosting. However, in certain liquid detergents the amide serves a three-fold purpose in that it provides stability, detergency and suds boosting. Accordingly, to eliminate or simply reduce the amide level would cause a loss in detergency and physical stability, and thus is not a practical solution to the problem.

Other efforts have been made to cope with the sudsing problem by employing a suds depressant in combination with a detergent composition. For example, US. Pat. No. 2,954,347 indicates that the suds-forming ability of detergent compositions solely dependent on anionic synthetic detergents, can be depressed by incorporating into the compositions a mixture of saturated fatty acids containing at least 50% fatty acid having 16 to about 31 carbon atoms and at least 5% having at least 20 carbon atoms.

US. Pat. No. 2,954,348 similarly suggests that the sudsing power of anionic non-soap synthetics can be depressed by incorporation into the compositions, a nonionic component which acts synergistically in combination with a mixture of fatty acids containing from 14-31 carbon atoms, provided the mixture contains at least 50% by weight of compounds having at least 16 carbon atoms in the molecule.

Applicant has found that notwithstanding the teachings of the prior art, the problem of producing a controlled sudsing detergent composition containing both an anionic detergent and nonionic amide-type detergent, is not simple. This conclusion stems from the fact that these detergent systems have varying properties in regard to phase stability which effect clarity of the dispersion as manifested by layering of the components due to partitioning of soluble materials. Accordingly, the addition of known agents which depress suds formation also tend to destabilize the mixture.

Applicant has found, however, that controlled sudsing anionic detergent compositions containing nonionic amide-type detergents can be stabilized by the inclusion of a select group of saturated fatty acids in critical proportions.

SUMMARY OF THE INVENTION Stable anionic controlled sudsing detergent compositions are afforded by incorporating into the composition a select group of saturated fatty acids in critical proportions in combination with a nonionic amide-type surface active agent.

Accordingly, an object of the present invention is provision for a heavy-duty anionic detergent composition having controlled sudsing power. Another object of the present invention is provision of a stable aqueous heavyduty detergent composition. Still another object of the present invention is provision of clear, phase stable heavyduty liquid detergent compositions having controlled sudsing capabilities under washing conditions and suds eliminating capabilities under rinse conditions.

DESCRIPTION OF THE INVENTION It has been found that stable, controlled sudsing anionic heavy-duty liquid detergent compositions which exist in the form of clear, macro-molecular colloidal dispersions (of the anionic surfactant in an aqueous medium) can be prepared by the addition of particular and exact levels of an alkanolamide in combination with a select group of saturated fatty acids.

Accordingly, the homogeneous detergent compositions of the present invention comprise an aqueous solution of from about (a) 1-15% (preferably about 340%) by weight of at least one alkali metal salt of a non-soap synthetic anionic detergent selected from the group consisting of biodegradable alkyl and alkaryl sulfonates and sulfates and alkylpolyethoxy sulfates;

(b) 49% (preferably 68%) by weight of at least one hydrotrope selected from the group consisting of alkali metal or ammonium salts of benzene or a monoor dialkyl substituted benzene sulfonate wherein the alkyl groups have 1-3 carbon atoms;

(c) 1-9% (preferably 2-7%) by weight of at least one nonionic N-(C -C alkanol substituted C -C alkaneamide;

(d) 05-45% (preferably 15-25%) by weight of at least one alkali metal salt of a fatty acid selected from the group comprising natural and synthetic C -C fatty acids, wherein the total amount of soap and nonionic amide represents from about 3.5-9'% (preferably 3.56%) by weight of the composition and the ratio of the soap to nonionic detergent from about 1:2-1:11 (preferably 1:2-1z4).

In addition to the aforementioned, the composition may also contain (e) 15-30% by weight (preferably 16-25%) of a detergent builder; and

(f) 2-10% (preferably 2-5%) by Weight of a buffering or anticorrosiye agent.

Depending on the final use to which the compositions of the present invention are to be employed, other ingtedients may also be incorporated. Example of other optional ingredients are perfumes, colorants, fabric softening agents, fungicides, germicides, enzymes, fluorescent dyes, antiredeposition agents such as carboxymethylcellulose, organic solvents and bleaches such as sodium perborate.

The anionic surface active agents used in the present invention are preferably linear alkyl or monoor dialkyl, benzene sulfonates or sulfates and preferably mixtures thereof wherein the alkyl chain has 1-18 (and preferably 10-18) carbon atoms and their alkali metal salts, preferably the potassium salts.

These compounds have the general formula of:

I II III IV wherein x is an integer of 1-5; Z is an integer of 1-3; R is an alkyl chain of 1-18 carbon atoms, at least one R having from 10-18 carbon atoms; and Y is an alkali metal or ammonium cation.

Typical alkyl sulfonates of Formula I include the sodium and potassium salts of decyl, dodecyl and octadecyl sulfonates.

Representative examples of benzene sulfonates of Formula II include higher alkyl benzene sulfonates containing 10-18 carbon atoms (e.g., sodium or potassium salts of decyl, dodecyl or octadodecyl benzene sulfonates) wherein the alkyl group is attached to any of the unsubstituted ring carbons.

Representative examples of alkyl sulfates of Formula II include sodium and potassium, salts of linear tridecanesulfate and octadecane sulfate.

The C -C alkylpolyethoxy sulfates represented by Formula IV are compounds prepared by introducing alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide into linear long chain (C -C alcohols and sulfating the resulting ethoxylated alcohol with oleum.

Hydrotropes used in the composition of the present invention are alkali metal salts of benzene sulfonate, monoor dialkyl substituted benzene sulfonates wherein the alkyl chains contain 1-3 carbon atoms. The alkyl benzene sulfonates include such compounds as toluene sulfonate, ethyl benzene sulfonates, isopropyl benzene sulfonates and m-, p-xylenes and preferably mixtures thereof. The term hydrotrope as used herein means an agent which will water-solubilize the main surface active agents used in the composition.

The builders which may be used in the composition of the present invention include inorganic-type builders such as pentapotassium tripolyphosphate, pentasodium tripolyphosphate, tetrapotassium pyrophosphate, tetrasodium pyrophosphate, tripotassium orthophosphate, trisodium orthophosphate as well as the organic builders.

The biodegradable organic builders include the alkali metal salts of the acid esters formed by reacting a polysaccharide with a cycle anhydride. Typical examples of the aforementioned include the sodium salts of starch maleate, succinate, glutamate and phthalate. Other organic builders that may be employed are well known in the art and include the alkali metal salts of ethylene diamine tetraacetic acid, nitrilotriacetic acid, gluconic acid,

4 citric acid, dihydroxyethyl glycine and the like as described in US. Pat. No. 3,332,880 incorporated by reference herein.

The nonionic detergents used in the present invention in combination with the select group of C -C acids are N-substituted C -C monoand diloweralkanolamides of fatty acids, having from 12-18 carbon atoms. Suitable N-substituted alkanolamides include lauric diethanolamide, oleic diethanolamide, myristic diethanolamide, tallow diethanolamide, lauric monoethanolamide and lauric isopropanolamide.

The soaps which form a critical part of the present invention are the alkali metal salts (sodium and preferably potassium) of fatty acids derived from national sources such as coconut oil (and accordingly known as coco fatty acid), babassu, ouri-curi, palm-kernel, ucuhuba and synthetic C 0, C 2, C acids and mixtures thereof.

When a mixture of fatty or synthetic acids are employed, it is important that the mixture contain at least 63% by weight of acids containing 10-14 carbon atoms and not more than 10% of acids containing 8 carbon atoms or less and not more than 27% of acids containing 16 carbon atoms or more.

In the preferred embodiment, the most suitable mixtures are those containing a predominance of C and C acids (i.e., 55-100%) although such mixtures may also contain minor amounts of up to 18% of acids having 10 carbon atoms or less and/0r up to 27% of acids having 16 carbon atoms or more.

Variation in fatty acid composition meeting the above specifications can fall within the range of fatty acids derived from coconut and other nut oils high in lauric and myristic acids including babassu, ouri-curi, palmkernel and ucuhuba. For example, any fatty acid mixture containing the following acid mixtures may be employed in the present invention:

Other heavy-duty liquid detergents which may be used in the present invention are those described in US. Pat. No. 2,895,182 and 2,994,665. By incorporating the fatty acid and alkyl-N-substituted alkanolamides in the amounts indicated, there will be afforded phase stable, controlled sudsing detergent compositions similar to those described herein.

The compositions of the present invention are prepared by combining in a suitable vessel water, the anionic surfactant with the hydrotropic agent in the presence of excess alkali metal hydroxide to form the alkali metal salts of said compounds. The amide and fatty acid are then blended together in a separate tank and the blend then formed is added to the hydrotrope anionic surfactant mixture wherein the fatty acid is neutralized in situ to the sodium and potassium soap. The desired builder and silicate as well as other desired additives are then combined and suflicient water added to bring the mixture to the final concentration.

Table I sets forth a series of detergent compositions prepared in accordance with the aforementioned procedure containing various levels of alkanolamide and fatty acid soaps tested for stability at elevated temperatures and under freeze-thaw conditions.

The compositions were tested for stability (i.e., retention of clarity and lack of phase separation or precipitates) under freeze-thaw conditions by alternately subjecting the samples to the lower of the indicated temperatures for one day and at the higher indicated temperature for one day. The formulas were cycled between these two temperature extremes for a period of two weeks. Sample A,

which is a typical stable high-sudsing anionic commercial detergent, served as the control.

soap synthetic anionic detergent selected from the group consisting of alkali metal salts of biodegrada- TABLE I Formulation (percent) Component A B C D E F G H I J K L M KLAS 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10 10.0 10.0 Na xylene/toluene su1fonate 8.0 8.0 8. 0 8.0 8.0 '8.0 8.0 8 0 8.0 8.0 8 0 8.0 8.0 LDA 2.5 2.2 0.3 2.5 2.2 0.3 l 25 1. 75 2.25 LIPA 3.0 2.8 0.7 3.0 2.8 0.7 1.75 2.25 2.75 Kcocate 0.5 4.5 5.5 0.5 4.5 5 5 2.5 1.5 5.0 TKPP 20.0 20.0 .0 0.0 .0 0.0 .0 NTANa. 1 Na silicate (2.5 ratio)- 2. 5 2. 5 5 H2O 54.0 54.0 .0

STABILITY 70-125 F S S 0 F.70 F S S 1 Potassium linear alkylbenze sulfonate. 2 Laurie diethjan 'olamide (C12).

8 Laurie isopropanolamide (C12).

4 Tetrapotassil l'py ophosphate.

6 Nitn'lotn'acetate.

To illustrate the controlled suds effect produced by using a combination of alkanolamide and fatty acid in the amounts disclosed in the present invention, samples of the detergents set forth in Table I were tested for their ability to clean without undue sudsing (including rinse) according to the following procedure: a 6 1b. load fabric soiled with standard vacuum cleaner dust was washed in a standard automatic agitator-type washing machine using hot water. The suds produced during the wash and rinse cycles were measured and compared. The results of the test (Table II) indicate that anionic detergents containing a combination of alkanolamide and fatty acids in the amounts disclosed according to the present invention slightly lower the suds level during the wash cycle and either eliminate or virtually eliminate suds from the rinse cycle, whereas the control heavy-duty detergent (A) had a high suds level in both the wash and rinse cycle.

The samples of detergents were also subjected to the Terg-O-Tometer test wherein cleaning efliciency was determined by measuring the reflectance value of cleaned clothes with a Gardner automatic color difference meter, Model AC-3. Table III indicates that the stable, controlled sudsing detergent compositions of the present invention have cleaning properties equal to a similar heavyduty anionic detergent composition which did not have the suds depressants of the present invention.

TABLE II.-WASHING MACHINE SUDSING TESTS Without soil load With soil load Wash Rinse Wash Rinse Formula No. 1 suds 2 suds suds suds A. Control (no soap) 1V 1% 2 1% J. 1.5% K Cocate. 1% T 2 T I. 2.% K Cocate--- 1% 0 1% 0 1 Corresponding to formulas in Table I supra. 1 Suds level measured in inches.

TABLE III Average final re- Formula No. l fleetance Comment A. Control 64.0 B. 0.5% K Cocate 64. 2 No significant difference between J. 1.5% Cocate 64. 5 products via statistical analysis. I. 2.5% K Coca-ten... 64. 0

1 Corresponding to formulas in Table I supra.

ble alkyl and alkylbenzene sulfates, alkylethoxy sulfates containing 1-5 ethoxy groups and alkyl and alkylbenzene sulfonates, said alkyl groups containing 1-18 carbon atoms;

(b) from about 4-9% by weight of at least one hydrotrope selected from the group consisting of alkali metal or ammonium salts of benzene or monoor dialkyl benzene sulfonates, wherein the alkyl chain contains from about 1-3 carbon atoms;

(c) from about l-9% by weight of at least one nonionic detergent selected from the group consisting of [N-C C alkanol substituted C -C alkaneamides]: N-substituted C -C monoand diloweralkanolamides having from 1218 carbon atoms;

(d) from about 05-45% by weight of at least one sodium or potassium soap of which at least by weight is derived from a saturated fatty acid selected from the group consisting of natural and synthetic Cm-Cm fatty acids or a mixture containing a predominance of said acids, wherein the combined soap and nonionic amide detergent represent from about 3.5-9% by weight of the total composition and the ratio of soap to nonionic detergent is from about 1:2 to about 1:1; and

(e) the balance Water.

2. The detergent composition of claim 1 wherein the alkali metal soap is derived from a mixture of fatty or synthetic acids, said mixture containing at least 63% by weight of acids containing 12-14 carbon atoms and not more than 18% by weight of fatty acids of 10 carbon atoms or less and not more than 27% of acids containing 16 carbon atoms or more.

3. The detergent composition of claim 2 wherein based on the total weight of the composition, the nonionic detergent is present in an amount of from about 27% and the soap is present in an amount of about 1.5-2.5 said nonionic detergent and soap together representing 3.56% of the composition and said ratio is 1:2-1z4.

4. The composition of claim 2 wherein said nonionic is selected from the group consisting of lauric monoethanolamine and lauric isopropanolamide and mixtures thereof.

References Cited UNITED STATES PATENTS 3,354,091 11/1967 Hearn et a1. 252-117 X 3,533,954 10/1970 Davies 2521 17 X 2,954,347 9/1960 St. John et al 252121 X 3,234,138 2/1966 Carroll et al 252-117 X MAYER WEINBLA'I'I, Primary Examiner US. Cl. X.R. 252--DTG. 14, 121 

